Electric fire-alarm apparatus



(No Model.)

G. M. STEVENS,

ELECTRIC FIRE ALARM APPARATUS. 8 No. 884,875. Patented June 19, 1888.

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UNITED STATES PATENT OFFICE.

GEORGE M. STEVENS, OF CAMBRIDGE, MASSACHUSETTS.

ELECTRIC FIRE-ALARM APPARATUS.

SPECIFICATION forming part of Letters Patent No. 384,875, dated June 19,1888.

Application filed March 12, 1888.

To all whom it may concern:

Be it known that I, GEORGE M. STEVENS,

a citizen of the United States, residing at Cambridge, in the county ofMiddlesex and State of Massachusetts, have invented a new and usefulImprovement in Electric Fire-Alarm Apparatus, of which the following isa specification, reference being had to the accompanying drawings.

My invention relates to an improvement in signal-boxes of an electricfire-alarm apparatus, its object being to provide means whereby while analarm is being given from any box on the circuit the devices forreleasing orpermitting the action of the mechanism in a box for causingan alarm cannot be operated by the lever which is to be pulled forgiving an alarm.

My invention consists in the devices and combinations of deviceshereinafter set forth, and specifically pointed out in the claims.

In the drawings, Figure 1 shows so much of a signal-loox and mechanismtherein embodying my invention as is sufficient for illustration of thesame. Fig. 2 is a section and plan, and Fig. 3 a section and side view,of certain parts shown in Fig. 1.

As usual in this class of signal boxes, there is a case, A, secured toand within an outer case, B. To give an alarm, a person opens the door 0of the outer case and pulls down a lever, D, which projects from thedoor E of the inner case. This lever I pivot to the door E or to a standthereon at a. This lever has an arm, I), fastened thereto, or integraltherewith, which is preferably of the shape and extends downward, asshown. A lever having one arm, a, nearly horizontal, and another arm,01, nearly vertical, is pivoted within the inner case at the sidethereof, at e, so as to swing in vertical planes. The arm d has a pin,f, fixed thereon, which extends, when the inner door is closed, througha slot, g, therein. The-arm c has the outer end portion pivoted to theother part at h, to swing horizontally. A flat spring, 2', tends to keepthis outer end portion in line with the balance of the arm 0.

The releasing device may be a lever having arms j and k and pivoted atZ, so that a pin, m, on a gear of the mechanism for causing the alarmmay meet the end of the arm k, and

Serial No. 267,088. (No model.)

is nearly vertical, and a spring, 02, tends to keep this lever inposition to meet the pin m, as shown. The spring at swings the leveragainsta fixed stop. (Not shown in the drawings, being connected withthe part broken away.) A projection, 0, on the pivoted part of the arm 0of the lever 0 d is so beveled that on pressing inward on said pivotedpart the armj of the leverj is will be moved sidewise, and hence thewhole leverj 7c swung so that the pin m will be released and the alarmmechanism be allowed to operate. I

An electro-magnet, F, is located in the inner case, its armature beingfixed to a lever, G, pivoted atp. A spring, q, tends to swing this leverand the armature away from the magnet. There is a pin, r, on the arni cof the lever c d, which may rest on the upper end of the lever G whenthe armature is in contact with the magnet and this lever G in theconsequent position.

A projection, H, fixed on the inner face of pp 75 N p 1 the outerdoor,is so located that when this door is closed it will engage with thepin f, and the lever c d will be held thereby in such position that thearm a will be raised.

Insulated brushes steo-operate with a wheel, I, for making and breakingthe electric circuit,

for giving an alarm .in the usual manner.

These brushes, in a signal-box from which no alarm is being given,remain on a contactspace of the wheel I, so that when no alarm is beinggiven from any signal-box on the circuit the circuit is closed. In thecircuit are the coils of the magnet F, as indicated. The

circuit being closed,on opening the outer door,

although the pin f will be released by the projection H, the lever c (Iwill swing and the arm 0 drop only a slight distance, since the pin 1'will meet the upper end of the lever G. The arm b'of the lever D willtherefore be opposite the pivoted portion of the arm a of the lever c d,and when the lever D is pulled said pivoted part of the arm 0 will beswung inward, so as to swing the lever j k and release the pin m. Thusthe alarm mechanism will be allowed to operate, but if, on opening theouter door, an alarm is being given from any box on the circuit, andhence the circuit is being broken, then the lever G will be released bythe mag by dotted lines in Fig. 1, that it will be below the arm b, andwill not be met and moved by this arm d when the lever D is pulled,andthe mechanism for giving an alarm will not be affected. Thus a person bypulling the lever D cannot cause any interference with an alarm beinggiven from any signal-box on the circuit. \Vhen the outer door isclosed, the lever c (I will be swung so as to be in position to have thearm 0 caught by the lever G or otherwise, as and for the purposes setforth.

I claim as my invention- 1. In an electric signal-box, the combinationof a door provided with a projection, H, a pivoted lever, c d, having anarm, c,to swing in a verticalplane, and located in said box, andprovided with a pin, f,to engage with said projection, said lever beingthus held against the action of gravitybetween the lever D to be pulledfor giving an alarm, and the device for releasing the mechanism formaking and breaking the circuit, substantially as setforth.

2. The combination, in an electric signalbox,of an electro-magnet, F,armature and lever G therefor, lever c d, provided with aprojection orpin, 1-, and projection 0, lever D to be pulled for giving an alarm, andthe relcasing-lever j k, substantially as set forth.

3. The combination of the outer door provided with a projection, H, alever, c d, having an arm, 0,to swing in a vertical plane, and providedwith a pin, f, to engage with said projection, and also provided with aprojection or pin, 1", an electro-magnet and armature and lever Gtherefor, and a lever, D, pivoted to the inner door, substantially asset forth.

4. The combination of the lever c d, having an arm, a, to swing in avertical plane, and swung by the outer door and upheld by a magnet,armature and lever G, a lever, D, to be pulled for giving an alarm, anda releasing device, as the lever j is, substantially as and for thepurposes set forth.

GEORGE M. STEVENS.

Witnesses:

O. H. RICHARDSON, EDW. DUMMER.

